On a pre-dawn Sunday, it's a curious sight. Thousands of people, young and old, are packed into a park on a city outskirts.

Spotlights cast an eerie glow on palm trees. Strange noises come from a public address system.

But the oddest thing about the gathering - at a time when most ordinary mortals are still tucked up in bed - is the mood of the occasion. Not your raucous pop concert crowd here. Instead, there's a sense of nervous anticipation, an uncanny feeling of a drama about to unfold. Armageddon? An alien visit?

People are swapping anxious looks. Long queues wait outside the portaloos.

Then, for anyone not aware of what is happening, a voice with an Australian accent makes sense of it all.

"Welcome to the Gold Coast half marathon," it drawls. "There are a record 10,000 of you competing today. Good luck to you all."

The crowd is herded into a line behind barriers. At the front are the lean and mean running machines, tweaking their hi-tech watches and raring to go in their lycra tops. At the back are the wannabe athletes, some counting on a little training and a lot of luck to get them through.

A hush descends for the countdown and the gun goes off. For those of us wedged in the middle of the field, it's an anticlimax. Nothing happens.

Then slowly the mass of humanity shuffles forward, a giant conga of flailing arms and legs. It breaks into a jog then a run. Shouts of "go hard" and "give it heaps" fade as we leave the start zone. As the sun rises over the sea, all we hear is the rhythmic pounding of shoes on tarmac.

For most of us, the next hour or two is a personal challenge, a test of stamina, legspeed and willpower. Many runners will enjoy the satisfaction of a fast time. The Gold Coast marathon, half marathon and 10km courses are all flat and fast.

But others will fall short of their goals, or not make it at all. Of the 10,342 half marathon entrants, 1124 fail to finish.

The faces of the runners betray their feelings, some cool and calm, others etched in pain.

All eyes are on Japanese marathoner Yuki Kawauchi as he dashes to the line, his face locked in a determined grimace - or is it a smile?

He certainly isn't smiling when he sees the time he has recorded - just one second outside the race record and a $5000 bonus prize.

"I pushed myself to the limit," he gasps into the microphones. "I really had to push myself. I will come back to beat the 2 hour 10 minute mark next time."

Kawauchi is in agony; his compatriot, Yukiko Akaba, is in ecstasy. She storms home to break the women's marathon record by more than two minutes. "My aim was to beat the course record so I'm very happy because I beat it by far," she beams.

There's lots of laughter, too, not only from the joy of completing the race but also at the wacky and wonderful sights. There's the guy who sweats around the course in a Superman costume. Or the dapper, straw-hatted competitor carrying a huge sousaphone brass instrument - at the same time playing the theme song from The Muppet Show.